Caspase inhibitor refers to a compound that can inhibit caspase activity, thereby regulating inflammation or apoptosis caused by caspase function. Among caspase inhibitors, irreversible inhibitor is known to show more effective inhibition activity since it irreversibly inactivates an enzyme to control apoptosis (Wu J. et al., Methods: A Companion to Methods in Enzymology 1999, 17, 320). The following compounds are known as irreversible inhibitor, and have 3-amino-5-fluoro-4-oxopentanoic acid moiety in common.

As diseases which can be treated or alleviated by administration of the above compounds, there are rheumatoid arthritis, inflammatory bowel disease, graft vs. host disease, sepsis, osteoarthritis, osteoporosis, acute and chronic myelogenous leukemia, meningitis, salpingitis, septic shock, cholangitis, colitis, encephalitis, endocarditis, glomerulonephritis, hepatitis, myocarditis, pancreatitis, Type I diabetes mellitus, multiple sclerosis, Alzheimer's disease, Parkinson's disease, hepatocirrhosis, etc.